Hurricane Charley nearing landfall after its rapid deepening phase

Rapid deepening is a condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. Hurricane Charley was the third named storm the second Hurricane, and the second major hurricane of the 2004 Atlantic hurricane season. A tropical cyclone is a storm system characterized by a low pressure center and numerous Thunderstorms that produce strong winds and Flooding The National Weather Service describes rapid deepening as a decrease of 42 millibars in less than 24 hours. The National Weather Service ( NWS) once known as the Weather Bureau is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. The hour (symbol h) is a unit of Time. It is not an SI unit but is accepted for use with the SI ^[1] However, this phrase is liberally applied to most storms undergoing rapid intensification.

Necessary conditions

In order for rapid deepening to occur, several conditions must be in place. Water temperatures must be extremely warm (near or above 30°C, 86°F), and water of this temperature must be sufficiently deep such that waves do not churn deeper cooler waters up to the surface. Sea surface temperature (SST is the water Temperature close to the surface The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 Wind shear must be low; when wind shear is high, the convection and circulation in the cyclone will be disrupted. Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively Convection in the most general terms refers to the movement of molecules within Fluids (i Usually, an anticyclone in the upper layers of the troposphere above the storm must be present as well — for extremely low surface pressures to develop, air must be rising very rapidly in the eyewall of the storm, and an upper-level anticyclone helps channel this air away from the cyclone efficiently. In Meteorology, an anticyclone (that is opposite to a Cyclone) is a Weather phenomenon in which there is a descending movement of the air and The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its Water vapor and The eye is a region of mostly calm Weather found at the center of strong Tropical cyclones The eye of a Storm is a roughly circular area and typically 30–65 km

Specific instances

In 2004, Hurricane Charley was approaching the west coast of Florida as a category two storm on the Saffir-Simpson scale of hurricane strength. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Hurricane Charley was the third named storm the second Hurricane, and the second major hurricane of the 2004 Atlantic hurricane season. Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the The Saffir-Simpson Hurricane Scale is a classification used for most Western Hemisphere Tropical cyclones that exceed the intensities of Tropical depressions When just off the coast, however, its sustained winds rapidly increased from 110 to 150 mph (along with a pressure drop from 965 to 941 mbar) in only three hours. Charley caused unprecedented destruction in the Punta Gorda area, and inflicted major damage across the state of Florida. Punta Gorda ( Fat Tip in Spanish is a city in Charlotte County, Florida, United States. ^[2]

In 2005, the minimum central pressure of Hurricane Wilma dropped from 981 to 882 mbar in 24 hours, including an incredible drop of 53 mbar in less than 6 hours. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Hurricane Wilma was the most intense hurricane ever recorded in the Atlantic basin. This is by far the fastest intensification of any Atlantic hurricane, and possibly the fastest intensification for any system in recorded history. ^[3] Typhoon Forrest in 1983 may have strengthened faster, deepening from 976 to 876 mbar in just under 24 hours, but pressure estimates for this storm were much less accurate. The 1983 Pacific typhoon season has no official bounds but most Tropical cyclones tend to form in the northwestern Pacific Ocean between May and November Year 1983 ( MCMLXXXIII) was a Common year starting on Saturday (link displays the 1983 Gregorian calendar) ^[4]

In 2006, Typhoon Chebi in the West Pacific was upgraded from a 65 mph tropical storm to a Category 4 equivalent typhoon in one advisory. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.

Explosive intensification

Explosive intensification is a more extreme case of rapid deepening that involves a tropical cyclone deepening at a rate of at least 2. 5 mbar per hour for a minimum of 12 hours. The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. Explosive intensification may occur only if conditions are near perfect, and therefore is rarely observed in the Western hemisphere. The Western Hemisphere, also Western hemisphere or western hemisphere, is a geographical term for the half of the Earth that lies West However, explosive intensification occurs regularly in the West Pacific basin, with the greatest frequency off the north coast of Australia where water temperatures can attain 30+ degrees C during mid-season. For a topic outline on this subject see List of basic Australia topics.

References

See also

• Tropical cyclone
• bomb (meteorology)